/*  
*********************************************************************************************************  
*                                                uC/OS-II  
*                                          The Real-Time Kernel  
*                                       MESSAGE MAILBOX MANAGEMENT  
*  
*                          (c) Copyright 1992-2005, Jean J. Labrosse, Weston, FL  
*                                           All Rights Reserved  
*  
* File    : OS_MBOX.C  
* By      : Jean J. Labrosse  
* Version : V2.80  
*********************************************************************************************************  
*/   
   
#ifndef  OS_MASTER_FILE   
#include "ucos_ii.h"   
#endif   
   
#if OS_MBOX_EN > 0   
/*  
*********************************************************************************************************  
*                                     ACCEPT MESSAGE FROM MAILBOX  
*  
* Description: This function checks the mailbox to see if a message is available.  Unlike OSMboxPend(),  
*              OSMboxAccept() does not suspend the calling task if a message is not available.  
*  
* Arguments  : pevent        is a pointer to the event control block  
*  
* Returns    : != (void *)0  is the message in the mailbox if one is available.  The mailbox is cleared  
*                            so the next time OSMboxAccept() is called, the mailbox will be empty.  
*              == (void *)0  if the mailbox is empty or,  
*                            if 'pevent' is a NULL pointer or,  
*                            if you didn't pass the proper event pointer.  
*********************************************************************************************************  
*/   
   
#if OS_MBOX_ACCEPT_EN > 0   
void  *OSMboxAccept (OS_EVENT *pevent)   
{   
    void      *msg;   
#if OS_CRITICAL_METHOD == 3                               /* Allocate storage for CPU status register  */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (pevent == (OS_EVENT *)0) {                        /* Validate 'pevent'                         */   
        return ((void *)0);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {      /* Validate event block type                 */   
        return ((void *)0);   
    }   
    OS_ENTER_CRITICAL();   
    msg                = pevent->OSEventPtr;   
    pevent->OSEventPtr = (void *)0;                       /* Clear the mailbox                         */   
    OS_EXIT_CRITICAL();   
    return (msg);                                         /* Return the message received (or NULL)     */   
}   
#endif   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                        CREATE A MESSAGE MAILBOX  
*  
* Description: This function creates a message mailbox if free event control blocks are available.  
*  
* Arguments  : msg           is a pointer to a message that you wish to deposit in the mailbox.  If  
*                            you set this value to the NULL pointer (i.e. (void *)0) then the mailbox  
*                            will be considered empty.  
*  
* Returns    : != (OS_EVENT *)0  is a pointer to the event control clock (OS_EVENT) associated with the  
*                                created mailbox  
*              == (OS_EVENT *)0  if no event control blocks were available  
*********************************************************************************************************  
*/   
   
OS_EVENT  *OSMboxCreate (void *msg)   
{   
    OS_EVENT  *pevent;   
#if OS_CRITICAL_METHOD == 3                      /* Allocate storage for CPU status register           */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
    if (OSIntNesting > 0) {                      /* See if called from ISR ...                         */   
        return ((OS_EVENT *)0);                  /* ... can't CREATE from an ISR                       */   
    }   
    OS_ENTER_CRITICAL();   
    pevent = OSEventFreeList;                    /* Get next free event control block                  */   
    if (OSEventFreeList != (OS_EVENT *)0) {      /* See if pool of free ECB pool was empty             */   
        OSEventFreeList = (OS_EVENT *)OSEventFreeList->OSEventPtr;   
    }   
    OS_EXIT_CRITICAL();   
    if (pevent != (OS_EVENT *)0) {   
        pevent->OSEventType    = OS_EVENT_TYPE_MBOX;   
        pevent->OSEventCnt     = 0;   
        pevent->OSEventPtr     = msg;            /* Deposit message in event control block             */   
#if OS_EVENT_NAME_SIZE > 1   
        pevent->OSEventName[0] = '?';   
        pevent->OSEventName[1] = OS_ASCII_NUL;   
#endif   
        OS_EventWaitListInit(pevent);   
    }   
    return (pevent);                             /* Return pointer to event control block              */   
}   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                         DELETE A MAIBOX  
*  
* Description: This function deletes a mailbox and readies all tasks pending on the mailbox.  
*  
* Arguments  : pevent        is a pointer to the event control block associated with the desired  
*                            mailbox.  
*  
*              opt           determines delete options as follows:  
*                            opt == OS_DEL_NO_PEND   Delete the mailbox ONLY if no task pending  
*                            opt == OS_DEL_ALWAYS    Deletes the mailbox even if tasks are waiting.  
*                                                    In this case, all the tasks pending will be readied.  
*  
*              err           is a pointer to an error code that can contain one of the following values:  
*                            OS_NO_ERR               The call was successful and the mailbox was deleted  
*                            OS_ERR_DEL_ISR          If you attempted to delete the mailbox from an ISR  
*                            OS_ERR_INVALID_OPT      An invalid option was specified  
*                            OS_ERR_TASK_WAITING     One or more tasks were waiting on the mailbox  
*                            OS_ERR_EVENT_TYPE       If you didn't pass a pointer to a mailbox  
*                            OS_ERR_PEVENT_NULL      If 'pevent' is a NULL pointer.  
*  
* Returns    : pevent        upon error  
*              (OS_EVENT *)0 if the mailbox was successfully deleted.  
*  
* Note(s)    : 1) This function must be used with care.  Tasks that would normally expect the presence of  
*                 the mailbox MUST check the return code of OSMboxPend().  
*              2) OSMboxAccept() callers will not know that the intended mailbox has been deleted!  
*              3) This call can potentially disable interrupts for a long time.  The interrupt disable  
*                 time is directly proportional to the number of tasks waiting on the mailbox.  
*              4) Because ALL tasks pending on the mailbox will be readied, you MUST be careful in  
*                 applications where the mailbox is used for mutual exclusion because the resource(s)  
*                 will no longer be guarded by the mailbox.  
*********************************************************************************************************  
*/   
   
#if OS_MBOX_DEL_EN > 0   
OS_EVENT  *OSMboxDel (OS_EVENT *pevent, INT8U opt, INT8U *err)   
{   
    BOOLEAN    tasks_waiting;   
    OS_EVENT  *pevent_return;   
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (err == (INT8U *)0) {                               /* Validate 'err'                           */   
        return (pevent);   
    }   
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */   
        *err = OS_ERR_PEVENT_NULL;   
        return (pevent);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {       /* Validate event block type                */   
        *err = OS_ERR_EVENT_TYPE;   
        return (pevent);   
    }   
    if (OSIntNesting > 0) {                                /* See if called from ISR ...               */   
        *err = OS_ERR_DEL_ISR;                             /* ... can't DELETE from an ISR             */   
        return (pevent);   
    }   
    OS_ENTER_CRITICAL();   
    if (pevent->OSEventGrp != 0) {                         /* See if any tasks waiting on mailbox      */   
        tasks_waiting = TRUE;                              /* Yes                                      */   
    } else {   
        tasks_waiting = FALSE;                             /* No                                       */   
    }   
    switch (opt) {   
        case OS_DEL_NO_PEND:                               /* Delete mailbox only if no task waiting   */   
             if (tasks_waiting == FALSE) {   
#if OS_EVENT_NAME_SIZE > 1   
                 pevent->OSEventName[0] = '?';             /* Unknown name                             */   
                 pevent->OSEventName[1] = OS_ASCII_NUL;   
#endif   
                 pevent->OSEventType = OS_EVENT_TYPE_UNUSED;   
                 pevent->OSEventPtr  = OSEventFreeList;    /* Return Event Control Block to free list  */   
                 pevent->OSEventCnt  = 0;   
                 OSEventFreeList     = pevent;             /* Get next free event control block        */   
                 OS_EXIT_CRITICAL();   
                 *err                = OS_NO_ERR;   
                 pevent_return       = (OS_EVENT *)0;      /* Mailbox has been deleted                 */   
             } else {   
                 OS_EXIT_CRITICAL();   
                 *err                = OS_ERR_TASK_WAITING;   
                 pevent_return       = pevent;   
             }   
             break;   
   
        case OS_DEL_ALWAYS:                                /* Always delete the mailbox                */   
             while (pevent->OSEventGrp != 0) {             /* Ready ALL tasks waiting for mailbox      */   
                 (void)OS_EventTaskRdy(pevent, (void *)0, OS_STAT_MBOX);   
             }   
#if OS_EVENT_NAME_SIZE > 1   
             pevent->OSEventName[0] = '?';                 /* Unknown name                             */   
             pevent->OSEventName[1] = OS_ASCII_NUL;   
#endif   
             pevent->OSEventType    = OS_EVENT_TYPE_UNUSED;   
             pevent->OSEventPtr     = OSEventFreeList;     /* Return Event Control Block to free list  */   
             pevent->OSEventCnt     = 0;   
             OSEventFreeList        = pevent;              /* Get next free event control block        */   
             OS_EXIT_CRITICAL();   
             if (tasks_waiting == TRUE) {                  /* Reschedule only if task(s) were waiting  */   
                 OS_Sched();                               /* Find highest priority task ready to run  */   
             }   
             *err          = OS_NO_ERR;   
             pevent_return = (OS_EVENT *)0;                /* Mailbox has been deleted                 */   
             break;   
   
        default:   
             OS_EXIT_CRITICAL();   
             *err          = OS_ERR_INVALID_OPT;   
             pevent_return = pevent;   
             break;   
    }   
    return (pevent_return);   
}   
#endif   
   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                      PEND ON MAILBOX FOR A MESSAGE  
*  
* Description: This function waits for a message to be sent to a mailbox  
*  
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox  
*  
*              timeout       is an optional timeout period (in clock ticks).  If non-zero, your task will  
*                            wait for a message to arrive at the mailbox up to the amount of time  
*                            specified by this argument.  If you specify 0, however, your task will wait  
*                            forever at the specified mailbox or, until a message arrives.  
*  
*              err           is a pointer to where an error message will be deposited.  Possible error  
*                            messages are:  
*  
*                            OS_NO_ERR           The call was successful and your task received a  
*                                                message.  
*                            OS_TIMEOUT          A message was not received within the specified timeout  
*                            OS_ERR_EVENT_TYPE   Invalid event type  
*                            OS_ERR_PEND_ISR     If you called this function from an ISR and the result  
*                                                would lead to a suspension.  
*                            OS_ERR_PEVENT_NULL  If 'pevent' is a NULL pointer  
*  
* Returns    : != (void *)0  is a pointer to the message received  
*              == (void *)0  if no message was received or,  
*                            if 'pevent' is a NULL pointer or,  
*                            if you didn't pass the proper pointer to the event control block.  
*********************************************************************************************************  
*/   
   
void  *OSMboxPend (OS_EVENT *pevent, INT16U timeout, INT8U *err)   
{   
    void      *msg;   
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (err == (INT8U *)0) {                          /* Validate 'err'                                */   
        return ((void *)0);   
    }   
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */   
        *err = OS_ERR_PEVENT_NULL;   
        return ((void *)0);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */   
        *err = OS_ERR_EVENT_TYPE;   
        return ((void *)0);   
    }   
    if (OSIntNesting > 0) {                           /* See if called from ISR ...                    */   
        *err = OS_ERR_PEND_ISR;                       /* ... can't PEND from an ISR                    */   
        return ((void *)0);   
    }   
    OS_ENTER_CRITICAL();   
    msg = pevent->OSEventPtr;   
    if (msg != (void *)0) {                           /* See if there is already a message             */   
        pevent->OSEventPtr = (void *)0;               /* Clear the mailbox                             */   
        OS_EXIT_CRITICAL();   
        *err = OS_NO_ERR;   
        return (msg);                                 /* Return the message received (or NULL)         */   
    }   
    OSTCBCur->OSTCBStat  |= OS_STAT_MBOX;             /* Message not available, task will pend         */   
    OSTCBCur->OSTCBPendTO = FALSE;   
    OSTCBCur->OSTCBDly    = timeout;                  /* Load timeout in TCB                           */   
    OS_EventTaskWait(pevent);                         /* Suspend task until event or timeout occurs    */   
    OS_EXIT_CRITICAL();   
    OS_Sched();                                       /* Find next highest priority task ready to run  */   
    OS_ENTER_CRITICAL();   
    if (OSTCBCur->OSTCBPendTO == TRUE) {              /* See if we were given the message              */   
        OS_EventTO(pevent);                           /* Timed out, Make task ready                    */   
        OS_EXIT_CRITICAL();   
        *err = OS_TIMEOUT;                            /* Indicate that a timeout occured               */   
        return ((void *)0);                           /* Return a NULL message                         */   
    }   
    msg                     = OSTCBCur->OSTCBMsg;   
    OSTCBCur->OSTCBMsg      = (void *)0;              /* Yes, clear message received                   */   
    OSTCBCur->OSTCBStat     = OS_STAT_RDY;   
    OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0;          /* No longer waiting for event                   */   
    OS_EXIT_CRITICAL();   
    *err                    = OS_NO_ERR;   
    return (msg);                                     /* Return the message received                   */   
}   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                       POST MESSAGE TO A MAILBOX  
*  
* Description: This function sends a message to a mailbox  
*  
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox  
*  
*              msg           is a pointer to the message to send.  You MUST NOT send a NULL pointer.  
*  
* Returns    : OS_NO_ERR            The call was successful and the message was sent  
*              OS_MBOX_FULL         If the mailbox already contains a message.  You can can only send one  
*                                   message at a time and thus, the message MUST be consumed before you  
*                                   are allowed to send another one.  
*              OS_ERR_EVENT_TYPE    If you are attempting to post to a non mailbox.  
*              OS_ERR_PEVENT_NULL   If 'pevent' is a NULL pointer  
*              OS_ERR_POST_NULL_PTR If you are attempting to post a NULL pointer  
*  
* Note(s)    : 1) HPT means Highest Priority Task  
*********************************************************************************************************  
*/   
   
#if OS_MBOX_POST_EN > 0   
INT8U  OSMboxPost (OS_EVENT *pevent, void *msg)   
{   
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */   
        return (OS_ERR_PEVENT_NULL);   
    }   
    if (msg == (void *)0) {                           /* Make sure we are not posting a NULL pointer   */   
        return (OS_ERR_POST_NULL_PTR);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */   
        return (OS_ERR_EVENT_TYPE);   
    }   
    OS_ENTER_CRITICAL();   
    if (pevent->OSEventGrp != 0) {                        /* See if any task pending on mailbox        */   
        (void)OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX); /* Ready HPT waiting on event                */   
        OS_EXIT_CRITICAL();   
        OS_Sched();                                   /* Find highest priority task ready to run       */   
        return (OS_NO_ERR);   
    }   
    if (pevent->OSEventPtr != (void *)0) {            /* Make sure mailbox doesn't already have a msg  */   
        OS_EXIT_CRITICAL();   
        return (OS_MBOX_FULL);   
    }   
    pevent->OSEventPtr = msg;                         /* Place message in mailbox                      */   
    OS_EXIT_CRITICAL();   
    return (OS_NO_ERR);   
}   
#endif   
   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                       POST MESSAGE TO A MAILBOX  
*  
* Description: This function sends a message to a mailbox  
*  
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox  
*  
*              msg           is a pointer to the message to send.  You MUST NOT send a NULL pointer.  
*  
*              opt           determines the type of POST performed:  
*                            OS_POST_OPT_NONE         POST to a single waiting task  
*                                                     (Identical to OSMboxPost())  
*                            OS_POST_OPT_BROADCAST    POST to ALL tasks that are waiting on the mailbox  
*  
* Returns    : OS_NO_ERR            The call was successful and the message was sent  
*              OS_MBOX_FULL         If the mailbox already contains a message.  You can can only send one  
*                                   message at a time and thus, the message MUST be consumed before you  
*                                   are allowed to send another one.  
*              OS_ERR_EVENT_TYPE    If you are attempting to post to a non mailbox.  
*              OS_ERR_PEVENT_NULL   If 'pevent' is a NULL pointer  
*              OS_ERR_POST_NULL_PTR If you are attempting to post a NULL pointer  
*  
* Note(s)    : 1) HPT means Highest Priority Task  
*  
* Warning    : Interrupts can be disabled for a long time if you do a 'broadcast'.  In fact, the  
*              interrupt disable time is proportional to the number of tasks waiting on the mailbox.  
*********************************************************************************************************  
*/   
   
#if OS_MBOX_POST_OPT_EN > 0   
INT8U  OSMboxPostOpt (OS_EVENT *pevent, void *msg, INT8U opt)   
{   
#if OS_CRITICAL_METHOD == 3                           /* Allocate storage for CPU status register      */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (pevent == (OS_EVENT *)0) {                    /* Validate 'pevent'                             */   
        return (OS_ERR_PEVENT_NULL);   
    }   
    if (msg == (void *)0) {                           /* Make sure we are not posting a NULL pointer   */   
        return (OS_ERR_POST_NULL_PTR);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {  /* Validate event block type                     */   
        return (OS_ERR_EVENT_TYPE);   
    }   
    OS_ENTER_CRITICAL();   
    if (pevent->OSEventGrp != 0) {                    /* See if any task pending on mailbox            */   
        if ((opt & OS_POST_OPT_BROADCAST) != 0x00) {  /* Do we need to post msg to ALL waiting tasks ? */   
            while (pevent->OSEventGrp != 0) {         /* Yes, Post to ALL tasks waiting on mailbox     */   
                (void)OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX);   
            }   
        } else {   
            (void)OS_EventTaskRdy(pevent, msg, OS_STAT_MBOX);  /* No,  Post to HPT waiting on mbox     */   
        }   
        OS_EXIT_CRITICAL();   
        OS_Sched();                                            /* Find HPT ready to run                */   
        return (OS_NO_ERR);   
    }   
    if (pevent->OSEventPtr != (void *)0) {            /* Make sure mailbox doesn't already have a msg  */   
        OS_EXIT_CRITICAL();   
        return (OS_MBOX_FULL);   
    }   
    pevent->OSEventPtr = msg;                         /* Place message in mailbox                      */   
    OS_EXIT_CRITICAL();   
    return (OS_NO_ERR);   
}   
#endif   
   
/*$PAGE*/   
/*  
*********************************************************************************************************  
*                                        QUERY A MESSAGE MAILBOX  
*  
* Description: This function obtains information about a message mailbox.  
*  
* Arguments  : pevent        is a pointer to the event control block associated with the desired mailbox  
*  
*              p_mbox_data   is a pointer to a structure that will contain information about the message  
*                            mailbox.  
*  
* Returns    : OS_NO_ERR           The call was successful and the message was sent  
*              OS_ERR_EVENT_TYPE   If you are attempting to obtain data from a non mailbox.  
*              OS_ERR_PEVENT_NULL  If 'pevent'      is a NULL pointer  
*              OS_ERR_PDATA_NULL   If 'p_mbox_data' is a NULL pointer  
*********************************************************************************************************  
*/   
   
#if OS_MBOX_QUERY_EN > 0   
INT8U  OSMboxQuery (OS_EVENT *pevent, OS_MBOX_DATA *p_mbox_data)   
{   
    INT8U      i;   
#if OS_LOWEST_PRIO <= 63   
    INT8U     *psrc;   
    INT8U     *pdest;   
#else   
    INT16U    *psrc;   
    INT16U    *pdest;   
#endif   
#if OS_CRITICAL_METHOD == 3                                /* Allocate storage for CPU status register */   
    OS_CPU_SR  cpu_sr = 0;   
#endif   
   
   
   
#if OS_ARG_CHK_EN > 0   
    if (pevent == (OS_EVENT *)0) {                         /* Validate 'pevent'                        */   
        return (OS_ERR_PEVENT_NULL);   
    }   
    if (p_mbox_data == (OS_MBOX_DATA *)0) {                /* Validate 'p_mbox_data'                   */   
        return (OS_ERR_PDATA_NULL);   
    }   
#endif   
    if (pevent->OSEventType != OS_EVENT_TYPE_MBOX) {       /* Validate event block type                */   
        return (OS_ERR_EVENT_TYPE);   
    }   
    OS_ENTER_CRITICAL();   
    p_mbox_data->OSEventGrp = pevent->OSEventGrp;          /* Copy message mailbox wait list           */   
    psrc                    = &pevent->OSEventTbl[0];   
    pdest                   = &p_mbox_data->OSEventTbl[0];   
    for (i = 0; i < OS_EVENT_TBL_SIZE; i++) {   
        *pdest++ = *psrc++;   
    }   
    p_mbox_data->OSMsg = pevent->OSEventPtr;               /* Get message from mailbox                 */   
    OS_EXIT_CRITICAL();   
    return (OS_NO_ERR);   
}   
#endif                                                     /* OS_MBOX_QUERY_EN                         */   
#endif                                                     /* OS_MBOX_EN                               */   

